Field
Various communication devices may benefit from network sharing. For example, network sharing may be beneficial for long term evolution on unlicensed band (LTE-U) and/or licensed-assisted access (LAA) cells operating on an unlicensed spectrum according to the third generation partnership project (3GPP). Further, LTE enhancements may be implemented for LAA to unlicensed spectrum, including LTE-U.
Description of the Related Art
The fast update of LTE in different regions of the world shows both that demand for wireless broad data is increasing, and that LTE is an extremely successful platform to meet that demand. At the same time, unlicensed spectrum is being considered by more cellular operators as a complementary tool to augment their service offering.
Unlicensed spectrum may not be able to match the qualities of the licensed regime. However, those solutions that allow an efficient use of unlicensed spectrum as a complement to licensed deployments have the potential to bring great value to 3GPP operators, and ultimately, to the 3GPP industry as a whole. Given the widespread deployment and usage of other technologies in unlicensed spectrum for wireless communications in society, it is envisioned that LTE would have to coexist with existing and future uses of unlicensed spectrum. Existing and new spectrum licensed for exclusive use by international mobile telecommunications (IMT) technologies will remain fundamental for providing seamless coverage, achieving the highest spectral efficiency, and ensuring the highest reliability of cellular networks through careful planning and deployment of high-quality network equipment and devices.
LAA should not impact/interfere with other systems, such as, for example, Wi-Fi, more than an additional Wi-Fi network on the same carrier. According to regulatory requirements, only certain amount of data can be transmitted without a listen before talk (LBT) mechanism, which may not be feasible for cell discovery and cell specific broadcast signaling. This may cause a problem that broadcast signaling space in unlicensed spectrum is limited. Further, it is assumed, for example, that primary synchronization channel (PSS)/secondary synchronization channel (SSS)/common reference signal (CRS) and system information are transmitted without LBT.
LTE-U/LAA is assumed to support network/radio access network (RAN) sharing which may be problematic because a public land mobile network (PLMN) identification (ID) may be quite long in size and all the necessary PLMN, such as, for example, a maximum of six (own PLMN+5 others), needs to be signaled.
As shown in FIG. 1, PLMN identity is coded, in approximately 12 bytes total, in 3GPP TS 36.331, section 6.3.4. In the worst case scenario for network sharing, the network would need to signal 6 PLMN identities, which equate to 6×12 bytes, totaling 72 bytes.
Complementing the LTE platform with unlicensed spectrum is a possible choice under the above considerations. It would enable operators and vendors to leverage the existing or planned investments in LTE/evolved packet core (EPC) hardware in the radio and core network, especially if “Licensed-Assisted Access” is considered a secondary component carrier integrated into LTE.